Crude oil transportation has been increasingly important for chemical industry, and to enhance the flowability of crude oil, various surfactants and amphipathic polymers have been utilized to form oil-in-water emulsions. As an alternative to traditional surfactants, nanoparticulate polymer brushes serve as an ideal scaffold to form Pickering emulsions with crude oil because of their large specific area, excellent stability, and tunable surface property. In our paper, a new type of oil-soluble polymer brushes was utilized to achieve stable crude oil emulsification by forming Pickering emulsions in water. By combining inverse emulsion polymerization and photoemulsion polymerization, poly(N-vinylcarbazole) chains with different lengths were successfully grafted onto the water-soluble poly(acrylic acid) core dispersed in hexane, and the novel series of oil-soluble latex polymer brushes features monodispersity, well-tuned size and fluorescence, and stability, as verified by dynamic light scattering, transmission electron microscopy, UV-vis and fluorescence spectra, as well as small-angle X-ray scattering. More importantly, the amphiphilic nature of the latex particles was successfully utilized to stabilize crude oil droplets in water by forming Pickering emulsions with apparent viscosity reduced by 99%, which is superior to most of the additives used in industry. Therefore, the oil-soluble core-shell latex particles could serve as promising candidates to be applied in petrochemical industry by improving the flowability of heavy crude oil during its exploration, transportation, and recovery process.